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If your computer is configured to dual boot between Microsoft Windows 95 or Microsoft Windows 98 and Microsoft Windows NT or Microsoft Windows 2000, when you upgrade from Windows 95 or Windows 98 to Windows 2000 Professional, you may receive any of the following error messages:

Windows 2000 Setup does not support upgrading from Windows if you have multiple operating systems installed. Setup will now exit.

-or-

Other Operating Systems Found

You cannot upgrade this Windows installation to Windows 2000,
because you have more than one operating system installed on your
computer. Upgrading one operating system can cause problems with
files shared by the other operating system, and is therefore not
permitted.

This message is displayed after the upgrade report has been generated.

Microsoft does not support upgrading Windows 95 or Windows 98 installations in a dual-boot configuration. Because some of these operating systems (Windows 2000 and Microsoft Windows NT 4.0) may share some files and folders (such as the Program Files folder), the other installed operating system could be affected.

During the Windows 95 or Windows 98 upgrade, some files that are specific only to Windows 95 or Windows 98 are deleted from the drive. Because the other operating system may be sharing these files, there is no way for Setup to determine that this may be the case.

To upgrade Windows 95 or Windows 98 to Windows 2000 Professional, you need to remove the other operating system. When you remove the dual boot operating system, make sure the following files are removed from the hard disk:

Ntldr

Ntdetect.com

Boot.ini

The %windir% (The directory where Windows NT 4.0 or Windows 2000 resides. It is usually in C:\winnt.)

NOTE: If you were dual booting Windows 95 or Windows 98 and Windows 2000, you may also need to remove the information in the C:\Program Files\Uninstall folder.